The present invention relates to a particular variable proportioning valve designed to proportion or meter two different liquids at constant pre-selected percentages under varying flow conditions.
The present invention is particularly useful in admixing or providing a foam solution wherein a foam liquid, or foam liquid forming solution or material, is admixed with water from a source such as a water hydrant, or a reservoir of the like, and wherein the output mixture will have a predetermined proportion of material or ratios for use in a foam-water fire fighting system. Other obvious uses for the invention and components thereof will appear hereinafter.
Apparatus and a system for plural fluid proportioning of the type in question, and particularly foam-water fire fighting systems wherein the demand for the foam-water mixture can be expected to vary considerably, is generally disclosed for example in prior U.S. Pat. No. 4,064,891.
Examples of valving apparatus used for admixing, or controlling the mixing of two liquid materials, exist in the prior art. Such prior art devices, apparatus and structures, however, have, in some instances, been of such complex structure and/or configuration as not only to reduce reliability of proportioning accuracy, but additionally create a problem of control, and/or repair, or modification of the apparatus to provide ultimately specifically different end flow discharges of two mixed fluids.
Of substantial significance for use in such systems is the new and novel variable proportioning valve of the invention. The valve is controllable to proportion or meter two liquids at constant pre-selected percentages, so that the output mixture of these two liquids, subsequent to being appropriately mixed, will remain in a pre-set cntrolled and constant ratio.
The novel valve incorporates, in a valve body, a flow control plug operable with a circular outlet port to determine the net flow area through which the liquid flows. The flow plug has a configuration whereby relative motion of the plug and the port varies the net outlet flow area.
The flow plug is provided with a seating surface of a nature which provides a means for complete flow shut-off through the valve.
The valve is of a structure permitting easy assembly and disassembly for removal of the plug for replacement of damaged plugs, and/or to incorporate in the valve plug bodies having specifically different configurations, and thereby serving to vary the output characteristics of the valve.
The valve is of a simple and yet highly efficient operating nature, and the various structural features thereof give improved operating characteristics.
The valve includes visual indicating means by which a user can pre-set the valve in order to vary the desired percentages or ratio of mixed liquids, and the setting is visually easily ascertainable through incorporation of a pointer and indicator plate showing a precise set angular position of the valve. This permits the valve to be quickly and accurately set to meet the desired conditions of use. Accurate setting of the valve to other desired percentages or ratios of mixed liquids can be readily accomplished during and under system flow conditions.
The valve structure incorporates means for varying the position of the flow plug, to vary the output flow therethrough, and uses a fast acting control for position of the plug to facilitate full opening of the valve in less than a 360.degree. rotation of a control handle, and greter than a 300.degree. rotation. The flow is infinitely variable from zero to maximum flow. The valve, generally speaking, is efficiently usable under high vibration environments and high inlet pressures, by use of dampening means serving to otherwise negate the tendency of these combined factors to cause the valve to go to the full open position; is lockable in any desired control position for the predetermined and pre-set output liquid ratio; can be used with corrosive liquids; provides readily attainable and repeatable positioning; visually accurately and easily indicates the valve setting position; permits all valve components to be removed from within the valve body without removal of the valve overall from the system; permits ready flow character alteration by change of the plug element; and generally results in a highly improved balanced proportioning system, with highly improved overall end results.
Additional advantages, objects and features of the invention will be more readily apparent from the following detailed description of an embodiment of the novel valve and a system incorporating the new valve structure.